I'm not exactly sure what you're asking but <em />I'll give it a go.
A = x -6
A) 26 minus x
b)8 times x
c)760 minus x
d)2.79 divided by x

a. 9:00 AM is the 60 minute mark:

b. 8:15 and 8:30 AM are the 15 and 30 minute marks, respectively. The probability of arriving at some point between them is

c. The probability of arriving on any given day before 8:40 AM (the 40 minute mark) is

The probability of doing so for at least 2 of 5 days is

i.e. you're virtually guaranteed to arrive within the first 40 minutes at least twice.
d. Integrate the PDF to obtain the CDF:

Then the desired probability is

2 1/3 = 7/3
Both numbers should be improper fractions.
11/3 + 7/3 = 18/3
Now the fractions must be simplified
18 ÷ 3 = 6
So 11/3 + 2 1/3 = 6
D. spread through the body through a process called melanoma